This invention relates generally to devices and methods for performing cardiovascular and surgical procedures. Various cardiovascular, surgical and other interventional procedures, including repair or replacement of aortic, mitral and other heart valves, repair of septal defects, pulmonary thrombectomy, coronary artery, bypass grafting, and neurovascular procedures, may require general anaesthesia, heart-lung machine (“on pump”), cardiopulmonary bypass, or arrest of cardiac function and treatment on the open chest.
In particular, this invention is concerned with the area aortic valve replacement procedure and focus is in patients with severely stenosed or damaged aortic valves. In the first instances, this new procedure will be performed on very sick patients who are not candidates for normal aortic valve replacement under normal open chest surgery where the patient is put on a heart-lung bypass machine. In the future, this invention could become the preferred method for placing an aortic valve in all patients since it is less invasive and better for the patient since it can be done on the beating heart through a thorocotomy instead of a sternotomy.
The invention also has applicability for 1) placement of apical grafts/canulas for Ventricular Assist Devices (VAD's), 2) for bypassing the mitral valve by creating a graft/canula with valve between the left atrium and left ventricle and 3) for creating access to the heart or to create a “port” through which other devices can be transferred or passed through. Such devices can be without any limitation heart valves, devices for repairing heart valves, other heart catheters, fluids.
Known techniques for performing major surgeries such as coronary artery bypass grafting and heart valve repair and replacement have generally required open access to the thoracic cavity through a large open wound, known as a sternotomy. Typically, the sternum is cut longitudinally (a median sternotomy), providing access between opposing halves of the anterior portion of the rib cage to the heart and other thoracic vessels and organs. An alternate method of entering the chest is via a lateral thoracotomy, in which an incision, typically 10 cm to 20 cm in length, is made between two ribs.
In particular this invention relates to the aortic valve replacement procedure, wherein the method of entering the chest is via a lateral thoracotomy and while the heart is beating, which is less invasive than through the sternum.
As noted, the invention also has applicability to VAD's, to bypassing the mitral valve and to accessing the heart. Such bypassing techniques could not only be used for aortic valve replacement but also for any native valve replacement via a “bypass” circuit.
Risks and complications associated with open-heart surgery, which involves the use of cardiopulmonary bypass, aortic cross-clamping and cardioplegic arrest, are well known.
Within recent years, minimally invasive types of procedures for coronary artery bypass surgery have been developed which do not require stopping the patient's heart and the use of cardiopulmonary bypass. While attempts have been made to treat aortic valves off-pump via endovascular procedures, e.g., endovascular balloon valvuloplasty, such procedures may provide only partial and temporary relief for a patient with a stenotic valve. Moreover, the rapid restenosis and high mortality following balloon aortic valvuloplasty have led to virtual abandonment of this procedure.
It should be noted that “percutaneous” methods for putting in new aortic valves are under development. However, there still exists problems during these “catheter-based”/“Percutaneous” procedures. In these procedures, the catheter must go through the aortic arch and in many cases this area and the aortic valve itself is very stenosed and calcified. So there is a very big risk of dislodging these calcified parts thus causing a stroke. Stroke from regular aortic valve replacement is a well known complication and occurs in 6-7% of procedures. By using a by-pass, any contact is avoided with the calcified aortic arch and the native vessel thus eliminating the risk of stroke in these patients.
Thus, there is an ongoing need for minimally invasive devices and techniques for treating patients suffering from diastolic dysfunction and directed to aortic valve replacement procedure. There is also a need for improved VAD placement, for bypassing the mitral valve and for accessing the heart. As such, it is desirable to provide such a procedure which is relatively simple and is easier to perform than conventional cardiovascular or surgical procedures and reduces the time and cost of the procedure. Moreover, it is desirable to provide such devices and procedures that obviate the need for cardiopulmonary bypass, can be used on a beating heart, involves endovascular or less invasive surgical techniques, and can be used by surgeons.